1. Field of the Invention
The present invention concerns an actuator for directing an incident light beam onto a fixed surface external to the actuator with a variable angle of incidence.
Without this being limiting on the invention in any way, an actuator of the above kind may be required in an analyzer including a cell containing a biochemical sample to be analyzed, for example. The measurement is performed by illuminating the sample through a fixed pupil with a beam that has to impinge on the sample at an angle that can be varied. In an analyzer of this kind the cell must be at a location that must not be encumbered with the means for producing and/or conveying the mobile beam. Also, it must be possible to manipulate the cell containing the sample without interacting with the device illuminating the sample.
2. Description of the Prior Art
Prior art devices for deflecting a light beam at an angle that can be varied are not suitable for the above application.
One well known example is an oscillating mirror onto which a light beam is directed and which reflects the beam at twice the angle at which it impinges on the mirror. The direction of the beam can be varied by pivoting the mirror about an axis in its own plane, possibly in a dynamically oscillating manner if the mirror moves continuously to and fro. However, in an arrangement of the above kind, the pupil through which the beam passes is necessarily on the mirror itself. Thus it cannot be applied to an analyzer as described above because the mirror would encumber the analysis cell and the sample could not be manipulated correctly.
An aim of the invention is to provide an actuator of the general kind indicated above which meets the two-fold requirement of being able to be placed at a location relatively far from the pupil through which the beam must pass and of not encumbering that location.